2C-B HBr

[shishigami]

I was reading through PiKHAL and saw that Shulgin said of 2C-B HBr "There are many complicated salt forms, both polymorphs and hydrates, that can make the isolation and characterization of 2C-B treacherous."

I was wondering what exactly the chemical equations of all these forms would be and why they would form.

 

[scureto1]

They form because of different conditions in the microenvironment of the crystals as they form. Factors such as temperature, availability of water, concentration of the compound the crystals are forming from, etc., all have an effect on the form the salt takes. Then, in a crystallization, once the crystal forms, it will retain that form until it is dissolved again, which is something a chemist would generally avoid, since it would be working backwards.

A good, simple example of hydrates to read about is the wiki of magnesium sulfate. Its most common forms are MgSO4 * 6H2O and MgSO4 * 7H2O. The asterisks there should be a dot. It just means that the crystal of the magnesium sulfate has X number of water molecules attached to it and has reached a lower energy level by binding those water molecules, and is thus more stable in that form. The reason it makes the isolation and characterization difficult is because 20mg (or any dose) of the *6H2O form would contain a bit more of the actual MgSO4 than a 20mg dose of the *7H2O, because the water is contributing to the mass, but will not contribute to the effect that the compound has on the body.

I only know the general format of the chemical formulas for those though, I don't know what the salt forms actually are for 2C-B HBr though, and I don't know if there is literature out there that has analyzed the subject.

Hope this was useful and not just a repeat of parts you already knew.

 

[shishigami]

That was what I was looking for. I knew about different forms of salts like hydrates and all but was blanking on what exactly could happen.

For polymorphism (which I just looked up and is defined as a chemical having more than one crystalline structure) wouldn't the 2C-B HBr still be uniform as far as mass goes? 20 mg of a pretty crystal is still the same amount as 20 mg of a not so pretty one.

 

[sekio]

Yes, but it frustrates identification of which hydrate you might have because each hydrate can have multiple crystal forms.

 

[adder]

Salts are like a web. When you read, e.g. amphetamine hydrochloride or it's written amphetamine * HCl, then imagine H(+) cations are at a further distance from Cl(-) anions and in reality the structure of it looks like that (for one of possible isomers):

  CH - CH   H   H   H
 //    \\   |   |   |
CH      C - C - C - N(+)---H  Cl(-)
 \     /    |   |   |
  CH = CH   H   CH3 H

In 100mg of amphetamine base you've got a lot of amphetamine molecules. When it's in a form of salt, it creates a web. Thanks to ionic bonds, water solutions of salts conduct electricity. You can look it up what I'm writing about checking sodium chloride in wikipedia.

If 1 molecule of water "adds itself" to a salt, it "builds itself" into such a web, so the crystals under microscope look different.

This is how it looks like for a hemihydrated salt of an organic base and an inorganic acid - codeine phosphate hemihydrate, it's a part of the structure with two cation molecules, two H2PO4 anions and one water molecule. When dissolved in water, water from the molecule will of course go to the solution as H3O(+) and OH(-) ions. But otherwise water molecule is built in the web. And the formula may be misleading: Codeine * H3PO4 * 1/2 H2O or rather C18H22NO3(+) * H2PO4(-) * 1/2 H2O. Anhydrous Codeine phosphate structure looks different than codeine phosphate hemihydrate structure.

The same goes for hydrates of 2C-B hydrobromide and anhydrous 2C-B hydrobromide.

 

[AlkaloidsEye]

That was an informative reply. Thank you Adder